You know how sometimes you can look at a conductor and wonder what their actual function is during the concert? It looks as if their beat is difficult to follow or it seems as if the orchestra is playing along with very little input from him or her, and you have to assume that it’s all in the conductor’s face, or that all the work took place during the rehearsals. Well, this is absolutely not the case with Mostly Mozart Music Director, Louis Langrée, who conducted Mozart and Debussy with the BSO this weekend. From the very first note I felt as if I could have played for him—had I had the aptitude—from the auditorium! It is marvelous to listen to a conductor like this because he makes the architecture of the music so clear. It was as if Langrée was sculpting the music in the air as he conducted—from the delicate grace notes that he indicated in his left hand, to the way he lead a crescendo from a crouched position to a fully extended explosion of energy. It was also clear that he respected the professionalism of the musicians and only conducted when he needed to. At times, he would elegantly rest his left hand on the rail behind the podium as the music took care of itself, and at one point he invited the cellos to play with just a very simple gesture. It was a joy to watch.